The present invention relates to a tool holder, and particularly to a tool holder for a high-precision machining center. More particularly, the present invention relates to a collet actuator for use in a tool holder.
Tool holders are typically used to mount machine tools such are drills, reamers, or grinders to a drill press, machining center, or other machining device. A spindle on the machining device spins the tool holder and the machine tool mounted thereon relative to a workpiece to drill, ream, grid, or otherwise machine the work piece into a desired shape.
Some tool holder are configured to be removed easily from the machining device to facilitate tool holder replacement and quick change-over between machine tool types or sizes, or to replace worn machine tools. Typically, a machine tool is first gripped by the tool holder and then the tool holder itself is mounted to the machining device.
According to the present invention, a tool holder includes a body formed to include a collet chamber and a collet-mover chamber, a coilet mounted for movement in the collet chamber, and a collet mover positioned to lie in the collet-mover chamber and coupled to the collet to move the collet relative to the body. The collet includes a tool-gripping surface arranged to define a tool-receiving chamber adapted to receive a machine tool therein.
The collet moves along a central axis of the body between a tool-grip position to cause the tool-gripping surface to move radially inwardly toward the central axis to grip the machine tool in the tool-receiving chamber and a tool-release position to cause the tool-gripping surface to move radially outwardly away from the central axis to release the machine tool. The collet mover draws the collet along the central axis to the tool-grip position in response to rotation of the collet mover about an axis of rotation in the collet-mover chamber and pushes the collet along the central axis to the tool-release position in response to rotation of the collet mover about an axis of rotation in the collet-mover chamber.
In preferred embodiments, the body is formed to include a passageway and includes an exterior surface having an edge that defines an access aperture opening into the passageway. The tool holder further includes a driver positioned in the passageway to engage the collet mover to move the collet relative to the body to cause the tool-gripping surface of the collet to engage the machine tool. The access aperture provides access to the driver while the tool holder is mounted on a machining center so that an operator may use a small handle tool, e.g. an alien wrench, to rotate the driver in the passageway and thereby move the collet relative to the body to cause the collet to grip the machine tool while the tool holder remains mounted to the machining center. Therefore, removal of the tool holder from the machining center prior to removal of the machine tool from the tool holder is unnecessary.
Additional features of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived.